Pump.



A. G. WALLS.

PUMP.

APPLICATION FILED NOV.2I| 1917.

Patented June 25, 1918.

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ALEXANDER GROUNDWATER WALLS, 0F, PAISLEY, SCOTLAND, ASSIGNQR T0. WALTER MOG'EE: & SON, LIMITED, 01. PAISLEE, SCOTLAND.

PUMP.

Specification of Letters Patent.

Application filed November 21, 1917. Serial No; 203,114".

To all whom it may concern:

Be it known w that I, ALEXANDER; Gnonnn- WATER WALLS, a subject of the King of the United Kingdom of Great Britain andlreland, and residing at Paisley, Renfrewshire, Scotland, have invented a certain new and useful. ImprovementiinPumps, of which the following is specification.

This invention relates to piston pumps having a valve mounted co-axiallya with and movable relatively to the pistonorpistons, so devised that the inlet port or ports is or are covered and uncovered by the piston or pistons and the outlet port or ports formed ina stationary part, is or are covered and uncovered by the valve.

The invention is hereinafter more particularly described as embodied in a pump having a pair of vertically movable pistons and adapted to deliver lubricating oil in an aero plane engine.

It will be understood, however, that the invention is applicable to a series of pistons mounted in line and of various diameters to suit the delivery required from each piston, so that many different parts of an engine may be lubricated with a suitable independent supply of oil at each revolution of the crank shaft.

The invention is illustrated in the accompanying drawing, in which Figure 1 shows one embodiment of the invention in diagrammatic form. Fig. 2 is a section showin the application of a spring jump ring in th valve. Fig. 3 shows the invention as applied to an aeroplane engine oil pump.

The same reference characters denote similar parts in the several views.

1 denotes a connecting rod engaging the gudgeon pin 2 and serving to lift and depress the upper piston 3 of a pair of pistons. The piston 3 has an extension or rod 4... similar to a piston rod, upon which is slidably mounted coaxially with the piston 3 a valve 5 of cylindrical form and of slightly larger diameter than the piston 3. The extension 4 is prolonged through the valve 5, and carries at its lower end a second or lower piston 6 which may differ in diameter from the upper piston 3 but must in any case be of less diameter than the valve 5.

As the valve 5 is larger in diameter than the pistons 3 and 6, the cylinder 7 is provided with a recess of larger diameter than the bore for the pistons, and such recess is conveniently formed, as. shown in F ig. 1, by boring the cylinder to three different diameters, one for the piston 3, one to fit the valve-5,; and one to fit the'liner 8,. which in turn is bored to fit the piston 6. It will be seen that thevalve 5 slides in a stationary part.

In; operation, the connecting-rod I de presses; the upper piston 3, whichis shown in Fig. 1, at the termination of its downward stroke,eXpel-1ing the liquid by the. outlet port 9. The lower piston 6 has now uncovered the inlet port 10, permitting the liquidto flow into the free space between the valve 5 and the lower piston 6.

On the upward or backward stroke, the lower piston 6 will close the inlet port 10, whereupon, by pressure on the liquid, it will force the valve 5 upward until the valve covers the outlet port 9 and uncovers the outlet port 11. The continued movement of the pistons expels the liquid from the bottom cylinder through the outlet port 11 and tends to establish a vacuum between the valve 5 and the upper piston 3.

At the termination of the upward stroke of the pistons the upper piston 3 will uncover the inlet port 12, thus filling the free space between the piston 3 and the valve 5, and the downward movement of the pistons will close the inlet port 12, propel the valve 5 to the position shown in the drawing, and expel the liquid from the upper portion of the cylinder through the outlet port 9, and tend to establish a vacuum between the valve 5 and the lower piston 6, until the inlet port 10 is opened, as shown in the draw ing, whereupon the cycle is complete.

In Fig. 2 the valve 5 is shown as fitted with two liners 14:, 15 of bearing metal with a space between to contain a spring jump ring 16, which, by catching in a recess 17 of the extension 4 at full up and down limit of the stroke, will. permit the valve 5 to be moved up and down suflieient to cover and uncover the outlet ports without the action of the pressure on the liquid in the lower portion of the cylinder, or will act as an aid thereto.

In Fig. 3 the invention is shown applied to the oil pump case of an aeroplane engine of the Gnome type and in this instance the lower piston 6 is of smaller diameter than the upper piston 3, for which reason the lower end of the valve 5 is reduced to the diameter of the lower piston 6.

The relative positions of the pistons,valve, inlet and outlet ports in Fig; 3 are the same as in Fig. 1; it is to be understood, how,-

ever, that the outlet port 9 leads into a down- Wardly directed duct, similar to, but behind,

22, operating the connecting rods 1 which carry the gudgeon pin 2 fitted to the '3, and thus operating the pump.

What I claim is 1. In a pump of the character described,

piston in combination, a chamber 'havinginlet and outlet ports, a piston movable in said chamber and adapted to control the said inlet Copies of this patent may be obtained for port, said piston having a reduced extension, and a valve mounted on said extension coaxially with said piston and movable on said extension, said valve being adapted to control the said outlet port.

"2. In a pump of the character described, in combination, a chamber having inlet and outlet ports, a pair of pistons movable in said chamber and adapted to control the inlet ports', a rod connecting said pistons, and a valve disposed intermediate said pistons and c0axia1therewith,csaid valve slidable on said rod and adapted to control the outlet ports. r V

In testimony whereof I have signed my name. to this specification in the presence of two-subscribing witnesses. ALEXANDER GROUNDWATER WALLS. Witnesses:

' HENRY MAsoN,

FLORENCE HOUSTON.

five cents each, by addressing the "Commissioner of retentl, Washington, D. 0." o 

